The safety requirements that led Toyota, Honda and other Japanese carmakers to falsify certification tests may be overly stringent and outdated given advancements in automobile design and technology, fueling calls for their review.

Despite revisions since the standards were enacted in 1951, regulations haven¡¯t kept up with the times, Takaki Nakanishi, an analyst at Astris Advisory Japan, wrote in a report. Although Akio Toyoda, chairman of Toyota, apologized earlier this week for failing to take proper steps, he also pointed to gaps between tests carried out in the field and the procedures required during the certification process.

As government officials raided Toyota¡¯s headquarters on Tuesday, the carmaker halted shipments of three cars: Corolla Fielder, Corolla Axio and Yaris Cross. Even so, the latest round didn¡¯t include warnings over operational safety. There doesn¡¯t appear to be any evidence of an ¡°organizational cover-up at this stage¡± by the manufacturers, according to Nakanishi.

¡°This could present an opportunity to reform a certification testing system that¡¯s out of kilter with actual conditions,¡± Nakanishi wrote.

Toyota¡¯s three models in question account for less than 2% of the 11 million vehicles automaker produced last year. Shipment halts will impact two assembly lines responsible for the production of about 130,000 units a year, according to the carmaker.

The latest certifications probe comes on top of others disclosed over the past year that pose a reputational risk for the broader group of Toyota companies. In December, an internal probe of Daihatsu showed most of its vehicles had not been properly tested for collision safety. Toyota Industries also suspended all engine shipments in January after an investigation revealed it had falsified power-output figures.

The latest emerging incident is ¡°extremely regrettable,¡± Ken Saito, the minister of economy, trade and industry, said during a news conference in Tokyo, adding the agency is investigating the impact on suppliers and will respond appropriately.

Toyoda, grandson of the company¡¯s founder, cited an episode at a dealership where some maintenance steps were omitted when examining cars with improved performance and precision, resulting in them being tagged as fraudulent inspections.

¡°This will provide an opportunity for the government and original equipment manufacturers to work out what¡¯s best for customers, the competitiveness of the Japanese automobile industry, and how to go about the certification system itself,¡± Toyoda said.

The system requires auto manufacturers to notify the transport ministry in advance of the production and sale of new vehicles, to be examined for conformity with safety standards.

¡°In many cases even if the certification process was not followed exactly, tests that were effectively even more rigorous were subsequently conducted in many instances,¡± Arifumi Yoshida, an analyst at Citigroup Global Markets Japan, wrote in a report....